1. Field of the Invention
The invention relates to a display apparatus and a data read-out controller thereof. And more particularly, the invention relates to a display apparatus with a touch screen and a data read-out controller configured to read out the sensing signals of the touch screen.
2. Descriptions of the Related Art
Over recent years, flat panel displays have gradually replaced conventional cathode ray tube (CRT) displays. There are currently following categories of flat panel displays: organic light-emitting diode (OLED) displays, plasma display panels (PDPs), liquid crystal displays (LCDs), and field emission displays (FEDs). Among these flat panel displays, LCDs have many advantages, such as a small volume, a flat square panel, high definition and stable picture quality, as well as low power consumption and a lack of radiation. As a result, LCDs have been widely used in many electronic products such as mobile phones, screens, digital televisions and notebook computers.
In addition, touch control functions have been added into certain LCDs for more convenient operation. Generally, such an LCD is known as a touch LCD.
In the touch LCD, the touch display module outputs a plurality of sensing signals to the data read-out controller in response to the user's touch, and then the data read-out controller outputs data signals to a touch control chip individually. More specifically, each pixel on the display panel of the touch LCD is configured to output a sensing signal to the data read-out controller depending on the user's touch, and the data read-out controller outputs a data signal to the touch control chip in response to each of the sensing signals.
As shown in FIG. 1, a conventional touch LCD 1 comprises a display panel 11, a scanning signal generator 13, a plurality of data read-out controllers 151, 152, 153, . . . , 15n and a touch control chip 17. The display panel 11 comprises m rows (131, 132, 133, . . . , 13m)×n columns (111, 112, 113, . . . , 11n) of pixels, i.e., m×n pixels. The pixels in each of the columns are simultaneously and electrically connected to a single data read-out controller. For example, the pixels in the first column 111 of the display panel 11 are simultaneously and electrically connected to the data read-out controller 151, the pixels in the second column 112 of the display panel 11 are simultaneously and electrically connected to the data read-out controller 152, etc. Finally, the pixels in the nth column 11n of the display panel 11 are simultaneously and electrically connected to the data read-out controller 15n. These data read-out controllers 151, 152, 153, . . . , 15n are electrically connected to the touch control chip 17 individually. The sensing signals 121, 122, 123, . . . , 12n of the pixels in each column of the display panel 11 will be outputted to the data read-out controllers 151, 152, 153, . . . , 15n in sequence according to the timing sequence of a plurality of scanning signals 101, 102, 103, . . . , 10m generated by the scanning signal generator 13. When the sensing signals 121, 122, 123, . . . , 12n are read by the data read-out controllers 151, 152, 153, . . . , 15n, respectively, data 141, 142, 143, . . . , 14n will be generated and outputted to the touch control chip 17 individually for subsequent signal processing.
More specifically, each of the data read-out controllers 151, 152, 153, . . . , 15n is electrically connected to the touch control chip 17 through an output point. When the display panel 11 of the touch LCD 1 comprises 50 rows×100 columns of pixels, 100 data read-out controllers will be needed to read the sensing signals and also the 100 output points that will be needed to output data to the touch control chip 17. If the display panel 11 of the touch LCD 1 comprises 500 rows×1000 columns of pixels, 1000 data read-out controllers will be needed to read the sensing signals and also the 1000 output points that will be needed to output data to the touch control chip 17. This will increase the manufacturing cost, circuit complexity and power consumption of the touch LCD 1.
To reduce the manufacturing cost, circuit complexity and power consumption, manufacturers have chosen to manufacture touch LCDs that can read out the sensing signals and output data by using time division multiplexing to reduce the number of data read-out controllers and that of output points. However, if time division multiplexing is directly used to read out the sensing signals and output the data, the sensing signals read out by the individual data read-out controllers will have different charging times. This will lead to an error in reading out the sensing signals and make the data outputted to the touch control chip incorrect. As a result, the LCD will falsely depict the user's input.
In summary, although time division multiplexing may decrease manufacturing costs, circuit complexity and power consumption by remarkably reducing the number of data read-out controllers and output points, it is difficult to correctly operate. In view of this, it is important to reduce the number of data read-out controllers and output points while still decreasing the error of sensing signals.